// Assets/_Project/Scripts/Towers/ConstructionPhaseSet.cs
using UnityEngine;

namespace TD.Towers
{
    /// <summary>
    /// An ordered set of construction-stage visuals a build site transitions between as a
    /// tower is built — typically 3 assets (early → mid → late). A tower references its own
    /// set via <see cref="TowerDefinition.ConstructionPhases"/>; build sites fall back to a
    /// project-default set when a tower doesn't define one.
    /// </summary>
    /// <remarks>
    /// The entries are <b>shape</b> prefabs only. <c>BuildSiteVisual</c> applies the
    /// queued (green) / constructing / paused materials and the owner tint on top, so the
    /// phase assets don't need their own build-state materials. Keep them simple
    /// (single material) — the build site swaps the active phase's renderer material.
    /// </remarks>
    [CreateAssetMenu(fileName = "ConstructionPhaseSet", menuName = "TD/Construction Phase Set")]
    public class ConstructionPhaseSet : ScriptableObject
    {
        [Tooltip("Ordered construction-stage prefabs. Shown in sequence as the build " +
                 "progresses — e.g. 3 entries = early / mid / late thirds of the build.")]
        [SerializeField] private GameObject[] phases;

        /// <summary>Number of construction phases in this set.</summary>
        public int PhaseCount => phases != null ? phases.Length : 0;

        /// <summary>The phase prefab at <paramref name="index"/>, or null if out of range.</summary>
        public GameObject GetPhase(int index)
            => (phases != null && index >= 0 && index < phases.Length) ? phases[index] : null;
    }
}